Patent GB-766596-A (GB)
Title: Improvements in and relating to automatic sharpening machines
IPC: B24B3/04
Filed: 1954-08-31
Abstract: 766,596. Grinding milling cutters. HABIB, R. Aug. 31, 1954 [Sept. 3, 1953], No. 25235/54. Class 60 A milling cutter is given the necessary helical movement during sharpening by mounting it on a rotary spindle 5, Fig. 2, carried by a reciprocating carriage 2, Figs. 2 and 4, the rotation of the spindle being controlled, as the carriage reciprocates, by a feeler 23 which is moved vertically on the carriage by 'its engagement with an inclined cam bar 24 on the base of the machine and so controls the operation of a distributer 22 feeding pressure fluid to a piston-and-cylinder device operatively connected with a rotary sleeve 13a surrounding the spindle and driving the latter through a catch. The spindle 5 is rotatable in a headstock 4 on the carriage 2 which runs on bearings 3 on the machine base 1 so as to move the cutter in relation to the grinding wheel; a spring plunger 10, Fig. 2, locks the spindle in position when desired. The sleeve 13a is driven from the piston - and - cylinder device (20, Fig. 3, not shown) through rack-and-pinion gearing, and the catch operatively connecting the sleeve and spindle consists of a bolt 37, Fig. 5, on a spring- urged lever 35 carried by the sleeve engaging one of a series of notches 38, Fig. 2, in a disc 39 rigid with a sleeve 40 fixed to the spindle. Operation of the piston-and-cylinder device to provide the helical motion of the cutter during movement of the carriage in both directions is effected by the distributing valve 22, Fig. 4, as controlled by the feeler 23 co-operating with the inclined cam bar 24 which is mounted on the base so as to be adjustable for both inclination and height; the body 29 of the distributing valve is given a compensating follow-up movement by mounting it rigidly with an hydraulic cylinder 29a which slides vertically over its piston 30 (which is fixed to the carriage) under the control of the valve. The control for the indexing of the spindle consists of a second distributing valve 53 which is carried underneath the carriage and has a feeler 52 cooperating with a fixed abutment 51. The feeler 52 is released on the return movement of the carriage so that the valve 53 actuates an hydraulic cylinder 55, Fig. 5. The piston rod 56 of this cylinder is connected to a transverse slide 57 carrying a rack 59 which is urged upwardly by springs 63 into engagement with a gear wheel 61 arranged to rotate through further gearing 64, 65, 66 a ratchet-and-pawl drive 68, 69 operative upon the sleeve 40 and spindle 5. Actuation of the valve 53 by the abutmeint 51 causes leftward movement in Fig. 5 of the piston rod 56 with the result that a stop 75 on the latter releases a lever 73 from latching engagement with a spring- pressed plunger 71 which then diengages the lever 35 from its locking engagement with the disc 39; the sleeve 13a has rotated to the position in which the lever 35 can be so disengaged because the cam bar 24 is at this stage ineffective to control the valve 22. The continued leftward movement of the piston rod then causes the ratchet-and-pawl device 68, 69 to move the spindle through an indexing movement which ends when an abutment 82 on the piston rod engages the push member 83 of an auxiliary valve 84 controlling the cylinder 55, the spindle being then positioned for the next notch 38 to be engaged by the bolt 37 on the lever 35. The feeler 52 leaves the abutment 51 as the carriage continues its movement and the distributing valve 53 then restores the piston rod 56 to the position shown in Fig. 5 ready for grinding the next blade.